Answer: +5 D.
- A +2 D
- B +5 D
- C +20 D
- D -5 D
Correct answer: B. +5 D
Explanation: P = 1/f = 1/0.2 m = +5 D. Convex (converging) lenses have positive power.
Concave mirror ray construction: a ray parallel to the axis reflects through F, and a ray through F reflects parallel, locating the inverted real image. Image: Maxmath12, CC0, via Wikimedia Commons.
Concept context
Reflection, refraction, lenses, mirrors, total internal reflection.